A gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section and an exhaust section. In operation, air enters an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section through a hot gas path defined within the turbine section and then exhausted from the turbine section via the exhaust section.
In particular configurations, the turbine section includes, in serial flow order, a high pressure (HP) turbine and a low pressure (LP) turbine. The HP turbine and the LP turbine each include various rotatable turbine components such as turbine rotor blades, rotor disks and retainers, and various stationary turbine components such as stator vanes or nozzles, turbine shrouds and engine frames. The rotatable and the stationary turbine components at least partially define the hot gas path through the turbine section. As the combustion gases flow through the hot gas path, thermal energy is transferred from the combustion gases to the rotatable turbine components and the stationary turbine components. As a result, it is generally necessary to cool the various rotatable and stationary turbine components to meet thermal and/or mechanical performance requirements.
Typically, a cooling medium such as compressed air is routed from the compressor section through various cooling passages or circuits defined within or around the various rotatable and stationary turbine components, thus providing cooling to those components. One generally effective cooling technique involves directing or focusing a jet or stream of the cooling medium directly onto a surface of a corresponding rotatable or stationary turbine component, thus providing jet or impingement cooling to that component. However, in certain instances, jet or impingement cooling may inadvertently occur, thus resulting in undesirable thermal stresses through the material of the particular rotatable or stationary turbine component due to a large temperature differential between the cooling medium and the combustion gases. This may negatively impact the thermal/mechanical life of the particular rotatable or stationary turbine component, particularly where the component is formed from a composite or ceramic matrix composite CMC-type material such as in various components of the turbine shroud assembly.
Accordingly, a turbine cooling system that reduces thermal stresses in the various turbine hardware components, particularly a turbine shroud assembly, would be welcomed in the technology.